The old RS2 – based on the Audi 80 and co-developed by Porsche – was such a big deal, in fact, that you could be forgiven for wondering how far we’ve actually come in arriving at 2012’s RS4. A 0.1sec improvement in 0-62mph acceleration and a 11mph gain in top speed (if the RS4 is unlimited)? At a glance, that’s all there is between the 311bhp RS2 and the 444bhp RS4. RS2 managed 0-62mph in 4.8sec and was good for 163mph, RS4 achieves 4.7sec and is limited to 155mph (unlimited: 174mph). But luckily, evolution isn’t defined by the stopwatch.

The RS4 can carry more momentum through corners with even more verve, can decelerate more weight with even greater efficiency, and uses fuel much more diligently. The question that remains for today is this: can it paint a broader smile on the driver’s face?

Audi RS4 Avant: the steering character

The variable-rate electrically-assisted steering feels suspiciously light when we exit the parking area and continues to act with astonishing directness up to 25mph. On the open road above 50mph, however, weight, speed and response are back to normal.

In the new RS4, the steering calibration is determined by more parameters than ever, including vehicle speed, g-force, steering angle and turn-in velocity. Driving through the same bend with the steering first in Comfort, then in Auto and finally in Dynamic is a real eye-opener. When the car approaches its limit, the dynamic steering automatically adjusts the line ever so slightly to reduce understeer or oversteer. On split friction surfaces, this mild correcting motion enhances the directional stability under braking. Dynamic is my steering choice for the day. It doesn’t tie a knot in your arms through slow first-gear kinks, it’s feisty enough for fast, second-gear roundabouts, and it won’t slacken the reins through demanding third-gear esses.

How the new Audi RS4 feels off the leash

The new RS4 Avant is certainly a more polished communicator than the earlier monosyllabic RS5, and it is definitely fast enough for a car with the silhouette of an innocent holdall. What require further investigation are the other elements of the Drive Select menu, the new drivetrain combination as well as the chassis and the brakes.

The long fast sweepers through Upper Bavaria’s hops and asparagus country are an open invitation to put the car through its paces. The sport suspension, which felt crash-bang brittle through town just a few minutes ago, no longer suffers from muscle cramps at 100mph-plus. On the contrary: follow the winding rollercoaster roads at a pace, and you’ll soon appreciate the extra-stiff sidewalls, the 265-series footprint of the P Zero Pirellis and the larger diameter of our optional 20in wheels. Unlike magnetic ride, the cost-option Dynamic Ride Control (DRC) is a wholly mechanical set-up which varies the damper calibration the old-fashioned way by opening or closing a hydraulic valve. Diagonally linking the four shock absorbers, the system not only reduces body roll, brake dive and acceleration squat to a minimum,it also lowers the ride height by 20mm. And today it’s really working.

They tell me the RS4 can rustle up 26.4mpg – an impressive 25% more fuel efficient than last year’s model – but I’m afraid all I can confirm after this drive is that it’s still possible to empty the 61-litre fuel tank in 210 miles. I do it, with pleasure. The first part of the drive was spent with the stability programme in Sport mode, the second half with the system disabled altogether (as confirmed by a bright yellow ESP OFF warning sign).

Does the extra leeway make much difference? On a track, perhaps. In the wet, occasionally. But on public roads it takes a braver man than me to induce serious tail-out antics which call for a large empty stage, a brutal right foot and the transmission in Dynamic to avoid unwanted upshifts. In this programme, the chips will automatically blip the throttle as the ratios step down the ladder, the exhaust will upgrade from tenor to baritone at 4000rpm, and gears are whipped through with an eerily physical urgency. To keep the engine voice down in built-up areas, a simple pull at the gearlever is all it takes to move from hooligan mode into Drive and back again. Clever.

The RS4’s dynamic technology

With the new RS4, Audi has taken a step back towards towards more feedback and transparency. Take the recalibrated aluminium sports suspension, which offers a new level of responsiveness. It is flat and stiff and focused, but its communication tools – steering, tyres, brakes, torque flow –- are deeper and more complex than before. This is partly down to the re-engineered Quattro system, which boasts a crown-wheel centre diff instead of the previous Torsen device. The new layout warrants a faster and more efficient torque distribution, front-to-rear and side-to-side. In tandem with the ABS sensors, the uprated 4wd technology pairs an amazing dynamic grip with a new level of lateral control. The comparative image that comes to mind is a lizard running up a wet glass pane.

The extra-cost sport differential is a bit of a doubled-edged sword. It does curb understeer and oversteer, it can juggle up to 1300lb ft of torque between the rear wheels, it works equally well under full load and under trailing throttle, and its software can cope with a wide range of friction coefficients. But during our drive, the difference between Comfort and Dynamic is virtually undetectable.

While steering and accelerator are now well synchronised for effort and effect, the standard steel brakes feel heavy on initial impact. A little too heavy in fact. There is nothing wrong with the absolute deceleration on tap, but when you step on the pedal, the first response is ample counterpressure rather than a fangs-bared, confidence-inspiring bite. This idiosyncracy is more obvious up to 50mph than on the autobahn, where you instinctly hit the brakes hard. Ceramic brakes are available… for about £5000.

The new RS4's engine and drivetrain

In an engine world increasingly dominated by downsized and turbocharged powerplants, a high-revving, normally-aspirated 4.2-litre V8 is a rarity. Although the output has gone up from the old engine’s 416bhp to an even beefier 444bhp, the fuel consumption is down to 26.4mpg. Redlined at 8500rpm, the direct-injection 32-valve DOHC unit dishes up 317lb ft of torque from 4000 to 6000rpm.

The only available transmission is a seven-speed dual-clutch S-tronic which features a long-legged top gear to cut revs on high-speed journeys. The transmission offers a choice of three modes: Drive, Sport and Manual. Manual means no more automatic upshifts, which can be useful for cross-country blasts. Less critical but apparently obligatory in a car like this is the launch control, which yields particularly spectacular results with ESP off. There is no special button for this – all you need to do is floor the throttle and watch the clutch crucify itself. On paper, this is a high-end torque engine which needs to be pushed hard to flex its muscle. On the road, the V8 will eagerly pick up speed at 2000rpm, draw breath again at 4000rpm and then explode above 6000rpm. Like all RS models, the Avant on steroids combines a catapult-like take-off performance with a strong mid-range urge which would go on and on if the limiter didn’t save the lightweight powerhouse from self-destruction.

Verdict

Rather like the Alpina D5 or the Boxster S, the new RS4 is not primarily a numbers car. It doesn’t rely only on a cracking top speed, a best-in-class acceleration time or a record g-force to collect its brownie points. This Audi is stronger than the sum of its data. It may not be the fastest, but it has finally learned to open up and share its newly found talents with the driver. In more ways than one, the RS4 feels like an estate car relative of the Skyline GT-R. It is very quick where most competitors are off the pace. It relishes exploring the virtues of 4wd. It acknowledges that there is a fourth dimension beyond grip, traction and roadholding. It no longer concentrates on plotting the most efficient line from A to B. Instead, the midsize RS model has discovered fresh qualities such as balance, involvement, interaction.

To our immense relief – and hopefully also to Audi’s – it has succeeded in maturing from the pragmatic but soulless perfection of the early RS5 to a more accessible, more controllable and ultimately more competent Q-car. It is a descendant the RS2 can be proud of.